TRENTON — When the 2009 season began, there were plenty of expectations placed on Yankees catching prospect Jesus Montero. But no one had more expectations than the 19-year-old catcher, who hoped to get promoted from High-A Tampa to Double-A Trenton as quickly as possible.

After hitting .356 with eight homers and 37 RBI in 48 games with Tampa, Montero got his wish.

“I was doing everything really good because I wanted to get here fast,” Montero said. “Thank God they gave me the opportunity to be here right now.”

Since the beginning of last season, when he hit .326 with 17 homers and 87 RBIs for Low-A Charleston, Montero has put himself among the biggest prospects — because of his size and talent — not only in the Yankees farm system, but in all of baseball. The 6-foot-4, 225-pound Venezuelan, who recently was ranked as the third-best prospect in the game by Baseball America, played in Wednesday’s Eastern League All-Star Game and his second consecutive Futures Game last Sunday.

“People have taken notice, without a doubt,” Yankees general manager Brian Cashman said. “All he’s doing is outperforming the norm. . . . At that age it’s extremely impressive.”

“His work ethic is strong, and he’s hungry and he cares and he’s got ability. He’s got to maintain that as he moves up the ladder, but so far it’s nice to see he refuses to be denied.”

Montero’s bat has continued to force the Yankees’ hand to promote him. After getting Montero from Tampa last month, Trenton manager Tony Franklin has been impressed not only with his raw hitting skills, but with the young catcher’s ability to learn and adjust to what pitchers are showing him.

“[Pitchers] threw him a lot of breaking balls when he first got here, and he swung at them . . . he isn’t as much now. There are plenty of guys who have been in the majors 10 years who swing at bad breaking balls. It’s a measure of discipline, and he’s starting to gain some of that.”

As good as Montero’s bat has been, there have been just as many questions about his ability to stay behind home plate. Because he’s so big physically at such a young age, there have been plenty of questions about his prospects as an adequate defensive catcher. Despite those questions, at least one scout says he has the potential to stick there.

“I don’t see why, in a couple years, he wouldn’t be OK,” the scout said. “I have seen a lot worse, I will tell you that. When the bat plays, people overlook those kinds of things.

“The typical size is 6-feet or so and squatty, like [Yankees legend Thurman] Munson. . . . But guys have been getting bigger, stronger, quicker, and coordination is better in all sports. Who’s to say he’s just too big?”

The prospect of someone with Montero’s bat behind the plate has the Yankees front office, Cashman included, understandably excited. After having the luxury of a quality hitter behind the plate for the past decade in Jorge Posada, the Bombers hope to have his replacement within their system.

“More and more every day, and that’s a credit to [Montero],” Cashman said of his chances of continuing as a catcher. “There was no question on the bat. The question was whether he would stay at the catching position because of his size. He’s maintained a work ethic that we thought was possible, but there was fair scrutiny about it.

“I think he’s proving, without a doubt, that he has a chance to be an everyday catcher in the big leagues, and our organization is excited about that. We are excited about the bat, but now that he has a chance to remain behind the plate, that’s a whole different animal there.”

If it were up to Montero, there would be no doubt about where his future would lay on the field. Having grown up catching, it is the only position he’s interested in playing.

“I was catching since I was little,” he said. “I like to be a leader in the game. . . . You’re in charge of everything behind home plate.”

If Montero is able to stay anywhere near the pace he is on, the latest he will reach The Bronx is 2011, and it seems more and more likely he will find his way to New York as soon as next year. For Cashman and the Yankees, it’s looking more and more likely their signing of Montero for $1.65 million in October 2006 could be a pivotal one.

“Not every player you sign, whether domestically, amateur or internationally, you hit on,” Cashman said. “But it looks like an extremely important decision for us when we had the opportunity to sign him, and I’m glad we did.”